Electrical properties of copper and titanium-codoped zinc ferrites

In this study, the effects of Cu and Ti substitution on the sintering behavior, substitution mechanism, resistivity and dielectric properties of (Zn)(Cu(x)T(x)Fe(1.98-2x))O(3.97) were investigated using X-ray diffractometer, scanning electron microscopy, and dilatometer. The results indicate that codoped Cu(2+) and Ti(4+) can effectively promote zinc ferrite densification. For the samples with x=0-0.05. Cu(2+) and Ti(4+) ions dissolved into the spinet structure and mainly occupied the octahedral sites, which resulted in an increase in resistivity. For the specimen with x=0.1 and 0.2, the Cu-rich and Zn-rich precipitates occurred at the grain boundary, leading to a decrease in resistivity. The variations in dielectric constant for samples with various x values as a function of frequency can be explained using the space charge polarization arising from the differences between the conductivity of the various phases present. (C) 2008 Elsevier B.V. All rights reserved.